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Need to add another trick to your repertoire? Here’s a different way of writing with invisible ink.

• 1/2 cup of water
• 1/2 cup of vinegar
• Bowl or cup
• Cotton swabs
• Paper
• A spray bottle
• Cabbage juice (make this by chopping up a head of cabbage, simmering it in water until the water turns dark purple and straining it. Get help from an adult if you need it. Now, pour the cabbage juice into the bottle, and refrigerate it until you need it. You could also use blackberries, red onion or hibiscus flowers.)

1. First, mix the water and vinegar into a bowl or cup.
2. Think about a sneaky message (or a normal one for a test run.) Now, dip the cotton swab into the vinegar solution, and write your message on the paper.
3. When it dries, it will be invisible until you spray it with the cabbage juice, which reveals the secret writing.

How It Works:

Vinegar is a type of acid, which reacts to the pH of the cabbage juice. The cabbage juice serves as an indicator, telling us whether the ink was made with an acid or a base. If you were to substitute the vinegar with ammonia, for example, the cabbage juice would reveal a different color of writing because ammonia is a base, not an acid.